Preparation of Visible-Light-Driven Silver Vanadates by a Microwave-Assisted Hydrothermal Method for the Photodegradation of Volatile Organic Vapors

Abstract

A variety of visible-light-driven silver vanadates, including α-AgVO3, β-AgVO3, and α-Ag3VO4, were synthesized using a microwave-assisted hydrothermal synthesis method. UV−vis spectroscopy indicated that each of the silver vanadate particles obtained in the study had strong visible-light absorption with associated band gaps in the range of 2.2−2.5 eV. The α-Ag3VO4 crystalline sample with rich hydroxyl functional groups on the surface exhibited the highest degree of photocatalytic activity. The reaction rates of the photodegradation of isopropanol (IPA) and benzene vapors were approximately 8 times higher than those of P25 under visible-light irradiation. Furthermore, the active sites at which catalysts play a role as proton donors (Brønsted acidity) in the photodegradation of VOC were characterized by the temperature-programmed desorption (TPD) method in conjunction with the diffuse reflectance infrared Fourier transform (DRIFT) technique. In addition, the photocatalytic activities of microwave-assisted hydrothermal samples were higher than those of samples produced by conventional hydrothermal techniques. This was due to an increase in the specific surface area and additional hydroxyl functional groups on the surface. These results demonstrate that the microwave-assisted hydrothermal method is an efficient technique for the fabrication of visible-light-responsive silver vanadates with outstanding performance in the photocatalysis of VOCs.